[adrian_b]

Noon is when the Sun is at maximum height, so it is approximately half time between sunrise and sunset.

The time of the noon varies from place to place depending on the longitude.

In the beginning, every major town had its own local time, with noon at 12:00. After the time zones were introduced, noon should have been everywhere some time between 11:30 and 12:30.

With DST, you can have a difference of up to 90 minutes between noon and the official 12:00, but there are countries which occupy more than one time zone, but do not bother to have so many time zones as necessary to minimize the differences between noon and 12:00, so there are places where there can be more than 2 hours between the true noon and 12:00.

It does not matter how far east/west you are but only how the time zones are set in your country, together with the DST.

If you would want to use the traditional boy scout technique of finding the south using a watch and either the Sun or the Moon, you would need to know the hour of the true noon in that place, otherwise the angular errors would be excessive.